1. Field of the Invention
The present invention relates generally to cotton harvesters and, more specifically, to improvements in the chassis, unit and ground drives, and air system of such harvesters for providing better weight distribution, improved air flow, and increased accessibility, serviceability and productivity.
2. Related Art
Cotton harvesters such as the commercially available John Deere Model 9960 Cotton Picker include a plurality of row units supported from the forward end of a main frame. The main frame is supported for movement over the ground by rear steerable wheels and forward drive wheels located below the cab behind the row units. A water or cleaning solution tank is located behind the cab for supplying cleaning fluid to moistener columns in the row units. An engine with a fore-and-aft extending crankshaft is supported by the frame rearwardly of the drive wheels and behind a cage-type centrifugal fan. The fan is belt driven from a sheave on the crankshaft for rotation about a fore-and-aft extending axis. The fan output is offset from the harvester centerline and opens downwardly into a lower rectangular plenum having air outlets on the bottom and sidewalls. The nozzles located on cotton conveying ducts are connected to the outlets by flexible conduits which are routed from the plenum upwardly and forwardly around the solution tank and cab.
Some cotton harvesters have split air systems which utilize two fans, one for each side of the machine. Split systems require twice as many fan drives and longer lengths of air ducts and air hoses, which add to the weight and complexity of the harvester. Both the split and single fan systems have fan bearings that must be greased at regular intervals and are relatively difficult to access and service.
Increased cotton yields coupled with the use of more high capacity row units per machine require greater air flow to adequately convey cotton. The available air systems with outlets coming off at an angle to fan air flow require a relatively large number of parts, and the outlets are often removed a substantial distance behind and below the nozzle areas of the cotton conveying ducts so that long air tubes with complex horizontal and vertical routings are required between the fan and the nozzles. The relatively tortious and lengthy path between the fan output and the duct nozzle limits efficiency of most present air systems and additional cotton handling capacity can only be achieved by increasing the power to the fan.
Weight distribution on a cotton harvester is a significant design consideration and a continual source of difficulty. A large amount of the weight of cotton harvester has to be carried on the forward drive wheels. The weight distribution becomes more critical as the row harvesting capacity is increased by adding more row units ahead of the drive wheels and a larger basket to adequately handle the higher picking capacity of machine. In addition, the present water tank location directly behind the cab puts most of the weight of the tank and its contents on the front drive wheels. The close proximity of the water tank to the ducts of the pneumatic conveying system limits tank configuration and duct placement.
Providing adequate space for the hydraulic pumps that drive a cotton harvester and attachments has also been a continuing source of problems with conventional cotton harvester chassis configurations. The main hydraulic pump drives a hydro motor which powers a transmission for driving the ground wheels and providing row unit drive which is dependant on forward harvester speed. At high speeds, increased loads on components such as those in the spindle drive can increase maintenance and repair costs. Spindle speeds outside a generally acceptable range can also reduce picking efficiency. Recently, to increase harvester life and productivity, attempts have been made to add structure to vary row unit drum speed relative to spindle speed. Such attempts have been hindered by space limitations and the complexity of variable speed transmissions.
A fluid pump for delivering spindle cleaning liquid from the solution tank to the row units is typically powered from the conveyor fan by a belt drive. The belt drive is costly and adds maintenance requirements in a location that is not easily accessed.
Presently available chassis configurations on cotton harvester with fore-and-aft mounted engines typically utilize side mounted screens to filter dust and debris from the air for the cooling systems on the harvester. The hostile environment of the harvester requires that the screens be cleaned manually at regular intervals, for example, each time the basket is dumped, to avoid inefficient cooling and overheating.